• Korean Journal of Materials Research
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• 제9권1호
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• pp.86-91
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• 1999

We have fabricated high-$\textrm{T}_c$ superconducting $\textrm{YBa}_{2}\textrm{Cu}_{3}\textrm{O}_{7-x}$(YBCO) grain boundary junctions at a step-edge on (001) $\textrm{SrTiO}_3$(STO) substrates. A diamond-like carbon (DLC) film grown by plasma enhanced chemical vapor deposition were used as an ion milling mask to make steps on the STO (100) single crystal and was removed by an oxygen reactive ion etch process. The c-axis oriented YBCO and TO thin films were deposited epitaxially on the STO substrate with a step-edge by pulsed laser deposition. The grain boundary junctions were formed at the top and the bottom of the step. The junctions worked at temperatures above 77 K, and had I\ulcornerR\ulcorner products of 7.5mV at 16K and 0.3 mV at 77K, respectively. The I-V characteristics of these junctions showed the shape of the two noisy resistively shunted junction model.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2011년도 정기 학술발표대회
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• pp.66-66
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• 2011

중위도 이북의 건물에서 고층건물의 혹한기 연돌효과는 건물의 여러 가지 기능에 큰 영향을 미치며, 승강기 승강로는 화재시 차압 때문에 연기의 주된 전파통로가 된다. 외피의 밀폐성능을 높여 건물 내부의 연도효과를 줄일 수 있으나, 외피의 밀폐기능은 비상시 피난을 위해 피난경로를 개방하는 순간 일시에 무력화된다. 또한 건물 외피의 밀폐성능이 우수할수록 연돌효과 그 자체로써 건물외피에 미치는 구조적 영향이 커진다. 고층부의 연돌효과는 외피를 밖으로 밀어내는 작용이므로 풍하측에서는 마이너스 풍압에 더하여 건물 외피에 부담을 증가시킨다. 그러므로 고층건물에 발생하는 혹한기 연돌효과의 영향을 정리하자면 다음과 같다. ${\bullet}$ 건물 외벽 및 창문에 미치는 구조적 영향 ${\bullet}$ 제연 시스템의 기능 저해 ${\bullet}$ 승강기 문 개폐 장애와 소음 등 설비 기능의 부정적 영향 ${\bullet}$ 공조기능 장애 ${\bullet}$ 화재시 승강기 승강로 등 수직 샤프트를 통한 연기 전파 혹한기 건물 안팎의 온도차가 40K일 때 높이 600m인 초고층 건물 최상층에 발생하는 연돌효과에 의한 차압은 풍속으로 환산할 때 32m/s에 달한다. 그러므로 초고층 건물 설계시에는 최상층의 풍하측에 설계상의 예상 최대풍속에다 이러한 환산풍속을 더한 고속 풍력이 창문을 밖으로 밀어내는 것으로 보아야 한다. 또한 공조 및 환기시스템에서는 이러한 차압을 고려하지 않으면 고층부에서 환기 성능이 무력화될 수 있다. 다음과 같은 방법들을 이용하여 고층건물의 연돌효과를 효과적으로 줄일 수 있다. 1) 계단실의 연돌효과 저감 방법 계단실에 발생하는 연돌효과에 의한 차압은 계단실에 상승기류를 발생시킨다. 이러한 차압과 상승기류는 계단실 상하부를 개방하면 자연적으로 평형을 이루게 되므로 별도의 제어가 필요 없게 된다. 또한 화재감지기와 연동하여 상하부 외벽의 개구부를 열어두게 되면 피난상황에 따라 문이 여닫힘으로써 발생하는 압력상태의 변화를 고려할 필요가 없게 된다. 2) 승강기 승강로의 연돌효과 승강로의 상하부에 대규모 개구를 두면 대규모의 외기가 도입되어 상승 유동 후 배출되므로 승강로 내부 온도 저하로 연돌효과가 저감되고, 승강로로 유입된 연기는 대규모의 외기에 희석되어 농도가 낮아지고 대부분 외부로 배출된다. 3) 샤프트 복합효과를 이용하는 방법 거실 평면적에 비해 승강기나 계단이 아주 많고 누설틈새 등 개구의 면적 합계가 크면 샤프트들이 서로 복합효과를 이루어 연돌효과에 의한 차압이 줄어든다. 연돌효과 제어용 샤프트를 하나 더 보조적으로 설치함으로써, 보조샤프트에 의해 발생하는 차압으로 거실을 가압 혹은 감압하여 문제가 되는 차압을 어느 정도 상쇄할 수 있다.

• Journal of Korean Society of Steel Construction
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• 제20권2호
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• pp.237-246
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• 2008

The cross-sections of continuous multi-span beams sometimes suddenly increase, or become stepped, at the interior supports of continuous beams to resist high negative moments. The three-dimensional finite-element program ABAQUS (2006) was used to analytically investigate the inelastic lateral-torsional buckling behavior of stepped beams subjected to pure bending moment and resulted in the development of design equations. The flanges of the smaller cross-section were fixed at 30.48 by 2.54 cm, whereas the width and/or thickness of the flanges of the larger cross-section varied. The web thickness and height of beam was kept at 1.65 cm and 88.9 cm, respectively. The ratios of the flange thickness, flange width, and stepped length of beams are considered analytical parameters. Two groups of 27 cases and 35 cases, respectively, were analyzed for double and single stepped beams. The combined effects of residual stresses and geometrical imperfection on inelastic lateral-torsional buckling of beams are considered. First, the distributions of residual stress of the cross-section is same as shown in Pi, etc (1995), and the initial geometric imperfection of the beam is set by central displacement equal to 0.1% of the unbraced length of beam. The new proposed equations definitely improve current design methods for the inelastic LTB problem and increase efficiency in building and bridge design. The proposed solutions can be easily used to develop new design equation for inelastic LTB resistance of stepped beams subjected to general loading condition such as a concentrated load, a series of concentrated loads or uniformly distributed load.

• Journal of the Korean Institute of Landscape Architecture
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• 제41권2호
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• pp.83-92
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• 2013

This study was to identify the differences on cognitions for conservation on the Rice Terraces landscape between local residents and visitors. For this purpose, this study drew problems and implications through consideration about advanced studies and then carried out a survey of local residents and visitors. The results of this study analyzed five factors that are the components of cognition about the Rice Terraces landscape: production, policy, landscape, management, and revitalization. The Cognition of Rice Terraces landscape indicated that local residents had more positive evaluation than visitors did. In addition, there were indicated differences in most items. Particularly, the local residents had more positive evaluation than visitors did in production(rice paddy of fallow ground, form of traditional rice paddy, weeds), landscape(cultural value, footpath of rice field and stonewall), and revitalization(common program for local residents and visitors, village revitalization from festival and event). Visitors had a more positive evaluation than local residents in terms of policy(designation of a place of scenic beauty, direct payment) and management(cooperation of local residents and visitors). In consideration of these results, it needs to draw up measures that are able to build up a common cognition to overcome differences between local residents and visitors. It is based on the knowledge and opinions that visitors and local residents had concerning history, traditions, cultures and production.

• Journal of Navigation and Port Research
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• 제39권1호
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• pp.29-35
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• 2015

As the numbers of users of domestic passenger ships increased up to 14.5 millions at 2012, the numbers of ships accidents also increased as 2 times than ever. It will be very important to develop technologies related with safety design for onboard passengers and disclose the potential problems. This study performed consciousness survey on ordinary peoples' way finding who have not got any regular anti-disaster training, to develop evacuation models for evacuation feasibility studies. Followings are the results answered by 83 participants for 33 way finding questions. Respondents selected right ways more than 6~18% for 2 ways like T type, U type, Y type passages. But when there are some walkers and/or runners, respondents preferred to select the way where walkers or runners are. And more over the ratio of the ways that runners are on is comparatively higher than walkers. On 'ㅏ'type, 'ㅓ'type and 3 way type passages, even though the walkers and/or runners are affected to answerers, straight way were most preferred. And it is clear that peoples like bright passages. On the other hands, peoples responded as they like right, downward and near stairs more than left, upward and far stairs, respectively. and very few selected escalator and elevator for as evacuation stairs.

• The Journal of the Convergence on Culture Technology
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• 제6권4호
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• pp.331-337
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• 2020

The study analyzes the appropriate number of people per a household by applying an evacuation simulation to a 27-floor apartment in accordance with the NFPA 101 standard. The results of the analysis are as follows. First, if there are three people residing in each household, there would be 156 households in total, of which 85.25% were evacuated within 5 minutes. Second, 208 households with 4 residents were evacuated within 5 minutes. Third, if there are five people residing in each household, there would be a total of 260 households and 71.92% of residents were evacuated within 5 minutes. Lastly, 62.82% of the 312 households, each consisting of 6 people, were evacuated within 5 minutes. Measures to reduce evacuation time include determining the width of the stairs according to the number of people indoors, the number of floors in the building, the slope of stairs, and the users' characteristics, the design reflecting the ventilation conditions of the stairs, the installment of outdoor evacuation stairs, two-way stairs, evacuation lift, and the installation of an evacuation safety zone for people to evacuate outside of the building in the middle floors. In addition, measures, such as the mandatory installation of automatic emergency door open-close device to the rooftop, are required to facilitate rooftop evacuation.

• Journal of Korea Water Resources Association
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• 제55권1호
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• pp.99-109
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• 2022

This study was intended to suggest the applicability of stepped boulder fishway using the concept of traditional boulder weir, focusing on the problems of existing concrete pool-and-weir fishways installed in mountain streams. To achieve this purpose, a stepped boulder fishway was designed and constructed as a pilot project in consideration of ascending capacity of the selected target fishes. Under the given discharge conditions, the hydraulic characteristics of the fishway were investigated in the field, and the characteristics and ascending capacity of the fishes were compared and analyzed. The fishway had a short length and steep slope, but the mean drops between each baffle were the range of 0.15 to 0.29 m, and this range satisfied the limit condition of about 0.40 m, which was in the limit of the drop that target fishes can ascend. The mean velocities of each baffle and pool were 0.82 to 0.87 m/sec and 0.13 to 0.24 m/sec. This result satisfied the conditions of burst speed (10 to 30 times of body length) and mean velocity of the resting pool (7 to 25% of burst speed) for target fishes. Since the bottom surface of the pool formed of boulders had a gentle reverse slope and rotational flow did not occur, the efficiency of fishway can be increased, and it will also be possible to solve the maintenance problem by flushing bed materials.

• The Journal of the Convergence on Culture Technology
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• 제8권5호
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• pp.641-651
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• 2022

This research compares and analyzes evacuation time depending on the change in stair width in case of fire at Goshiwons. For this, a simulation has been conducted based on possible evacuation time according to the calculation method for the number of people admittable to a specific target for fire fighting equipped with accommodation. Currently, Gosiwon, which is classified as an accommodation facility (a total floor area of 500 m² or more), uses blind spots prescribed by the Fire Services Act, Building Act, and Parking Act to build a high-rise building on a small area of land, and most Gosiwon is transformed into a modified accommodation. This is in line with the owner's operating profit, so it is expected to show a continuous increase. Securing the golden time of Gosiwon evacuation time is the last bastion of Gosiwon residents who belong to the economically disadvantaged in our society, and we hope this study will serve as a starting point for discussions on revising related laws and regulations to establish a social safety net As a result of the evacuation simulation analysis, the evacuation time was the least when the width of the group and the evacuation stairs were expanded to 200cm, and the evacuation time of the existing building was reduced by up to 166.3 seconds by comparing 648.4 seconds and scenario 6. This analysis can be meaningful, in that the width of the evacuation stairs revision of related laws and regulations for the safety of multiplex available premises.

• Journal of the Korean Physical Therapy Association
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• 제8권2호
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• pp.41-51
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• 1987

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.293-298
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• 1998